COMMUNICATIONS

1. COMMUNICATIONS

2. LECTURE ONE: EVERYTHING! 1. How does Radio work? 1. Basic Radiotelephony procedures 2. Departure Procedures 3. En-route procedures 4. Arrival / Traffic Pattern Procedures 5. Communications Failures 6. Distress / Urgency Procedures

3. RADIO BASICS: SOUND Sounds make vibrations in the air called sound waves Your ear drum then receives the waves and vibrates at the same frequency Your brain then converts these received sound waves into electrical signals which the brain interprets

4. RADIO BASICS: FREQUENCY Frequency is measured in Hertz (Hz) 1 hertz = 1 wave past a given point per second 1,000 Hz = 1 kilohertz (kHz) 1,000,000 Hz = 1 megahertz (MHz) Human ear can hear between 20 - 20,000 Hz “The Audio Frequency Range”

5. RADIO BASICS: WAVE MOTION Waves are described by their shape and frequency Wavelength Frequency The number of cycles per second (the higher the frequency the shorter the wavelength) Amplitude The greater the amplitude the louder the sound 1 cycle If it took 1 second for this cycle to complete it would be equal to 1 Hz

6. RADIO BASICS: RADIO WAVES A radio can be “tuned” to a particular frequency. Pressure Waves Electromagnetic Waves Aircraft Transmitter / Receiver Antennae Control Tower Transmitter Receiver Pressure Waves This means the radio will only pick up sounds on that frequency But there is a problem...

7. RADIO BASICS: RADIO & SOUND WAVES Sound waves are 20 Hz – 20,000 Hz Suitable radio waves for transmission are 3 MHz – 300 MHz (VHF) Sound wave Any voice message will need to be superimposed onto a radio frequency – known as a CARRIER WAVE When you press the transmit switch you transmit a carrier wave Carrier Wave Your microphone then imposes your voice onto the carrier wave so that it can be transmitted

8. RADIO BASICS: RADIO WAVES: MODULATION The receiving equipment then “tunes out” the carrier wave so that only the sound wave is heard The superimposition of a sound wave on a radio wave is called MODULATION and it is achieved in 2 main methods AM AMPLITUDE MODULATION (AM) varies the amplitude of the carrier wave to match the sound wave FREQUENCY MODULATION (FM) varies the frequency of the carrier wave to match the sound wave FM

9. RADIO BASICS: VHF RANGE VHF Communications are line of sight The higher your aircraft is, the further away your receiving station can be There may be more than one station with the same frequency (such as Sywell and Compton Abbas) which are far enough apart to not interfere with each other In mountainous areas relay stations may be used to extend the effective VHF range

10. RADIO BASICS Frequencies should be found in the UK AIP (or national AIP) Most pilots will use a flight guide (AFE or Pooleys) to get the information required in a more user-friendly format

11. RADIO BASICS The frequency is selected on the radio box – there are 2 main types: Simple radio – the left hand side is the communications frequency (Large knob does pre-decimal point, smaller knob does post-decimal point) Twin radio – the left hand side is the communications frequency in use and the right hand can be changed (Outer knob does pre-decimal point, inner knob does post-decimal point) There will then be a “flip flop” button to exchange the frequencies

12. RADIO BASICS: MICROPHONE TECHNIQUE • Headsets serve 3 main functions: • To reduce the ambient noise for the wearer • To allow clearer understanding of received messages • To allow no-hands communications / transmissions Sidetone is where you can slightly hear yourself when you talk (like on a landline telephone) – it helps you to talk clearly and to talk at the correct volume! Best to have microphone just above top lip and speak slightly slower and at NORMAL VOLUME!

13. RADIO BASICS: PHONETIC ALPHABET Developed since 1886 to avoid confusion between transmitted letters Has been altered on a number of occasions but the current format which is international is:

14. RADIO BASICS: PHONETIC ALPHABET J K L M N O P Q R uliette ilo ima ike ovember scar apa uebec omeo A B C D E F G H I lpha ravo harlie elta cho oxtrot olf otel ndia S T U V W X Y Z ierra ango niform ictor hiskey -ray ankee ulu

15. RADIO BASICS: NUMBERS • Numbers should be transmitted with the following pronunciation: • 0 zero • Wun • Too • Tree • Fow-er • Fife • Six • Seven • Ait • niner In addition: Decimal “day-see-mal” Thousand “tousand”

16. RADIO BASICS: NUMBERS Transmitting frequencies: 121.500 MHz “wun two wun dayseemal fife” 126.550 MHz “wun two six dayseemal fife fife zero” 124.275 Mhz “wun two fower dayseemal too seven fife”

17. PRACTICE QUESTION! “How should the frequency 132.750 MHz be transmitted?” “Wun tree two dayseemal seven fife zero”

18. RADIO BASICS: AIRCRAFT CALLSIGN Use full aircraft callsign on first communication with a new frequency Only shorten the callsign once it has been shortened by ATC If you leave the circuit and stay on frequency, use full callsign again when calling for rejoin into the circuit Always use the full callsign if you believe that confusion may exist

19. RADIO BASICS: AIRCRAFT CALLSIGN If you initiate a call the station addressed is the first thing to say, then your callsign If you are responding to a call your callsign comes at the end to indicate you have finished talking In this way terms such as “Over” and “Out” are unnecessary

20. RADIO BASICS: SOME BASIC WORDS “Negative” No / That is incorrect / Permission refused “Affirm” Yes / That is correct (Note! Not affirmative!) “Standby” Be quiet – no need to acknowledge “Roger” I received your transmission (Note! This in no way means “yes”) “Break” Use to separate messages “Wilco” I will comply with your instruction There are many more! – Check either CAP413 (RT Manual) or Pilots Manual Book 7 for details

21. PRACTICE QUESTION! “If are asked by ATC “can you maintain altitude 2500 feet”, what is the correct response? Is it Roger, Wilco, Affirm / Negative or Comply?” Affirm or Negative

22. LISTENING OUT & READING BACK Always monitor the frequency in use – they may be trying to contact you! By listening to other transmissions you will be able to build up a mental picture of what is going on in the area You are required to read back: Runway clearances , runway in use, altimeter settings, frequency changes, Clearances (take off, land, en-route), transponder codes, taxi instructions, level / altitude / heading / speed instructions

23. AIR TRAFFIC SERVICES Remember though, that ATC are there for your benefit and not the other way around! You think a radar controller is seeing this… The radar controller sees… ATC is like Tetris – the sooner the screen is clear the better! If ATC instruct you to do something you are unable to do, would be illegal to comply with, or you don’t want to –tell them!

24. AIR TRAFFIC SERVICES: GENERAL Prevention of Collision between aircraft on the ground or in the air So why do we need Air Traffic Control? Prevention of Collision between aircraft and objects at aerodromes Expedite and maintain an orderly flow of traffic Provide advice and information for the safe and efficient conduct of flights Notification of and Cooperation with Search and Rescue Plus – someone to talk to!

25. DEPARTURE PROCEDURES: ATIS Before taxy you will need to know information about the runway in use, pressure settings and weather The Air Traffic Control Service Unit (ATSU) may give this to you There may also be an Automated Terminal Information Service (ATIS) A frequency with rolling airfield information (usually timed with “information A”, “information B” etc When you contact ATSU for taxy you would state “information B received”

26. DEPARTURE PROCEDURES: RADIO CHECKS Prior to taxy you may request a radio check from ATC or at any time you feel it necessary A “readability” scale is used to communicate how easily a transmission is heard: • Unreadable (transmission garbled and/or unintelligible) • Readable now and then (voice is coming and going) • Readable but with difficulty (concentration and quiet required to hear) • Readable (may have a small issue such as strength) • Perfectly readable (no difficulties)

27. AIR TRAFFIC SERVICES Area Control Centre (ACC) Services: Air Traffic Control Service for IFR traffic in airways Air Traffic Advisory Service for traffic on advisory routes Flight Information Service and Alerting Service Distress and Diversion Service Aerodrome Traffic Services: Air Traffic Control for traffic in ATZ or in the vicinity Aerodrome Control / Approach Control on busy aerodromes Flight Information Services: (FIS) Air / Ground Radio Stations Safetycom (134.75) Open FIR Air Traffic Services Lower Airspace Radar Service (LARS) Available up to and including FL195 within 30nm of the nominated unit

28. DEPARTURE PROCEDURES: TAXI When you request taxi you will be given instructions, usually with a clearance limitation For example: “G-CB taxi to holding point alpha, runway 24 right hand, QFE 1012” You need to read back ALL this information! Having a pen ready to take down taxi instructions is very helpful – especially at unfamiliar airfields. If in doubt, ask!

29. DEPARTURE PROCEDURES: READY TO GET AIRBORNE The phrase to use is “Ready for Departure” – the term “take-off” is only ever used as a positive clearance to take off and only by the tower initially This is an outcome from the enquiry into the 1977 Tenerife disaster where an aircraft took off without clearance to do so and hit another which was crossing the runway Investigators noted how the term “take-off” was used excessively and when communicating a clearance and a cancellation of clearance

30. DEPARTURE PROCEDURES: READY TO GET AIRBORNE Responses by the tower may be one of the following: “G-CB Hold Position” Don’t move! “G-CB Line up” Cleared to enter the runway but not to get airborne “G-CB Backtrack” Taxy along the runway to the other end and turn around “G-CB Cleared Take off” Enter runway and take off! “G-CB Take off at your discretion” Used at “uncontrolled” airfields where the controller is not licensed to give you a clearance – it is not an indication that it is safe to take off – it is still your responsibility to check all is well

31. PRACTICE QUESTION! “Is the phrase “GWACE after the landing Warrior Line up” a conditional or unconditional clearance?” Conditional – a clearance is given but the conditions under which you may accept it were given first

32. DEPARTURE PROCEDURES: FLIGHT INFORMATION SERVICE Once airborne and either inside the ATZ or within the vicinity of the ATZ you will receive a “Flight Information Service” from the ATSU If venturing further afield you will need to change the service received – more of which later!

33. PRACTICE QUESTION! “What does ATIS stand for” Automated Terminal Information Service

34. EN-ROUTE PROCEDURES Normally you will be advised when to change frequency but you can initiate a frequency change as well if you wish “G-CB frequency change Sywell Information 122.7” “G-CB change frequency to Wycombe Tower 126.550” Remember if you don’t want to change frequency and there is no reason why you should – tell them!

35. FLIGHT INFORMATION REGIONS UK airspace is divided into 2 Flight Information Regions – Scottish and London FIRs extend up to 24,500 ft (FL245) Upper Information Regions (UIRs) extend above this with the same sub-divisions Within this, airspace is sub-divided into 7 classes (A-G) and then also other areas and zones…

36. AIR TRAFFIC SERVICES The type of ATC provision depends upon types of traffic involved, density of traffic and meteorological conditions At Wycombe Air Park we have a full tower provision due to the mix of traffic – high wing light aircraft, low wing light aircraft, helicopters and gliders At weekends and on other busy days / periods there are two frequencies in use – Ground and Tower Wycombe Air Park is regularly logged as being busier than London Heathrow airport!

37. AIR TRAFFIC SERVICES: EN ROUTE Air Traffic Control outside Controlled Airspace (ATSOCAS) There are 4 levels of service you can request from a controller: BASIC SERVICE TRAFFIC SERVICE DECONFLICTION SERVICE PROCEDURAL SERVICE Which service you ask for depends on the level of service you require, your flight conditions and the station you are communicating with

38. EN-ROUTE: BASIC SERVICE Advice and information useful to the safe and efficient conduct of flights Aimed to give the pilot maximum autonomy Pilot responsible for: ATC responsible for: No requirements for monitoring flights or giving traffic information Have pressure setting information if asked Avoidance of Traffic Terrain Clearance Change heading, route or level without advising the controller Available to IFR and VFR but probably not appropriate for IMC

39. EN-ROUTE: TRAFFIC SERVICE Radar Based Service where the basic service is added to by radar-derived traffic information Only available from controllers with radar Pilot responsible for: ATC responsible for: Traffic Avoidance Terrain Clearance Navigation Level selection Identification of Aircraft Relevant traffic information Headings / Levels for sequencing but not deconfliction Available to IFR and VFR – advise controller if you are VMC if given a heading or level that requires flight into cloud

40. EN-ROUTE: DECONFLICTION SERVICE Surveillance based service so controller can control traffic through heading or level instruction and to achieve separation minima Requires 5nm lateral separation ad 3,000 feet vertically. Pilot responsible for: ATC responsible for: Terrain Avoidance Traffic Avoidance (if instructions are not followed) Own navigation or controlled nav Identification of aircraft Traffic information and avoiding action Heading and Level instructions Available to IFR and VFR – you will need to accept any heading or level instruction so not really suitable if you are VMC-only

41. EN-ROUTE: PROCEDURAL SERVICE Controller provides additional heading, level and time instructions to achieve deconfliction from PARTICIPATING traffic No radar facility so not all traffic will be avoided Pilot responsible for: ATC responsible for: Terrain Clearance Obtain clearance to change heading or level No identification required Deconfliction minima for participating traffic May issue squawks for other radar controllers Available to IFR and VFR but may require IMC flight – do not accept a procedural service if IMC is not legal

42. EN-ROUTE: POSITION REPORTS If you are not covered by radar, position reports may be required at regular intervals Aircraft Callsign Position Time Level Next Position Example: “G-WACH Aylesbury 42 2300 feet, estimate Silverstone 54” On-request reporting point Mandatory reporting point

43. EN-ROUTE: VDF VHF Direction Finding Some airfields are equipped to sense the direction from which a radio signal is being transmitted This can be helpful because they can steer you to the airfield just by a radio call from you Used by the emergency frequency 121.5 MHz to position fix lost aircraft – more of which later Flamborough Head VDF Station

44. EN-ROUTE: VDF “QDM” magnetic bearing that aircraft needs to steer to get to the station (+/- wind) Direction Magnetic “QDR” magnetic bearing of the aircraft from the station (+/- wind) Direction Radiating “QTE” true bearing of the aircraft from the station (+/- wind) True Emination

45. EN-ROUTE: VDF It is important to know how accurate the steers are that you are being given! If the accuracy is not at least Class B the controller may refuse to give VDF headings “QDM, QDM, QDM, Cranfield Approach, GWACE request QDM” “GWACE QDM 085 Class Bravo” You then steer the heading given +/- wind correction! The controller can update the heading after further QDM requests

46. EN-ROUTE: VOLMET VOLMET is a broadcast which gives weather information for a group of airfields on a continuous loop Each airfield will have information including: Aerodrome name Time of Report (zulu) Surface Wind Visibility RVR (if applicable) Weather (rain / snow etc) Cloud Temperature Dewpoint QNH Any significant trend Other Information

47. EN-ROUTE: VOLMET Useful prior to flight to get an overall picture of the weather situation Useful on longer flights to keep updated on weather trends Main one we would use is London South which continuously transmits 24 hours a day on 128.60 MHz for Birmingham, Bournemouth, Bristol, Cardiff, Jersey, Luton, Norwich, Southampton & Southend

48. EN-ROUTE: SPECIAL VFR Special VFR (SVFR) is used to allow pilots to fly in a controlled airspace that they would not normally be allowed access to (because cannot comply with IFR) • On a SVFR Clearance you must: • Comply with ATC instructions • Remain clear of cloud • Fly in the limitations of your licence • Comply with low flying regulations (Rule 5) • Remain clear of any ATZ unless specifically cleared to enter If you have a radio failure you should squawk 7600 and leave the airspace by the quickest routeing

49. EN-ROUTE: MATZ Specified airspace around a military aerodrome Clearance is not required to enter a MATZ but it is poor airmanship The ATZ within a MATZ is still controlled airspace It is good airmanship to request “MATZ Penetration” at least 15nm or 5 mins from the edge of the airspace 2,000 ft 3,000 ft agl 4 nm wide 5nm radius 5 nm long

50. EN-ROUTE: SAFETYCOM Not an air traffic control frequency – there is no ground station! 135.475 MHz Used for aircraft to communicate for collision avoidance and traffic intentions near airfields with no air traffic control Only use if below 2000 ft (or below 1000 ft above circuit height) and only within 10nm of the intended airfield This avoids congestion and “breakthrough” on a nationwide frequency